K&F Concept ND Filter Set for DJI Osmo Action 4: ND8+ND16+ND32+ND64, Light Reduction Adjustment, AGC Optical Glass, 28-Layer Nano Coating, Waterproof and Oil-Proof This is an ND filter set for the DJI Osmo Action. It can be attached to both Action 4 and Action 5. There are almost no scratches. Here is the Amazon link for details, but I purchased it directly from the manufacturer's store at the time. https://amzn.asia/d/7dfOenD